CN102448814B - Structure for assembly of the pressure bulkhead of an aircraft - Google Patents

Abstract

The structure comprises: a bulkhead ring (22) including a front portion and a rear portion which is inclined upwards and rearwards and by means of which the pressure bulkhead (1) is connected, a simple frame (18) which is connected to the front portion of the bulkhead ring (22), an extended flange plate (23) which is arranged between the front portion of the bulkhead ring (22) and the skin (6, 7), and tensioning attachments (24, 25) coupled between the extended flange plate (23) and the stringers (8, 9).

Description

Aircraft pressure partition wall assembly structure

technical field

The invention is designed for use in the field of aircraft design and manufacture in the aviation industry.

purpose of invention

As stated in the title of this specification, the object of the present invention is to provide an assembly structure for an aircraft pressure partition.

The pressure partition is the element that isolates the pressurized area at the rear of the aircraft. From a structural point of view, the element is concave in shape from the pressurized area side and is substantially hemispherical, so that the material of the partition wall can be fully utilized to absorb the load caused by the pressure difference, hereinafter referred to as the pressure load.

Another object of the present invention is to provide an assembly structure such that all the parts comprised by the structure can be easily produced in composite material, thus resulting in a reduction in weight, which is a decisive factor in the aviation industry.

Background technique

Typically, the pressure partition is assembled to the aircraft using a frame that separates the front and rear sections of the fuselage, which are the pressurized and unpressurized areas in the aircraft, respectively. In such constructions, the partition wall assembly, in addition to absorbing the pressure loads, must primarily be able to provide suitable strength for joining together the front and rear sections of the fuselage and adequately stiffen the fuselage.

To this end, the known pressure partition assembly comprises, as described below, a cylindrical symmetrical frame (following the contour of the fuselage) delimited by its symmetrical parts.

The frame includes a central web, an upper flange and a lower flange. Typically, the upper flange of the frame has a front and a rear.

The pressure partition is attached to the rear of the upper flange of the frame, projecting obliquely upward and rearward at an angle relative to the skin. This inclination is determined by a line tangent to the pressure partition wall, which slopes at an angle of approximately 60 degrees as a guide. Typically, the partition walls are secured to the frame using mechanical fastening means such as rivets.

In addition to the above, the skins of the front and rear fuselage sections are secured to the lower flanges of the frame by means of reinforcing plates called butt straps placed between the lower flanges of the frame and the skins. Typically, the connection between the lower flange of the frame and the skin is accomplished using mechanical means such as rivets.

In order to ensure the continuity of the connection of the front and rear parts of the fuselage and thus the continuity of the forces absorbed by the stringers and skins of the corresponding parts, a known assembly structure comprising some front tension fittings and rear tension fittings is included . These tension fittings connect the stringers and skin of the forward section of the fuselage to the stringers and skin of the rear section of the fuselage using frames. Each of these tension fittings is secured to the stringer on one side and to the frame on the other side by mechanical means such as rivets. Tension fittings are typically secured to the frame with a central web and with the front of the frame upper flange. Post tension fittings are usually secured to the frame using only the center web of the frame.

It is known to place a structural element on the side of the pressurized area, mainly consisting of struts connected between the frame and another reinforcement frame connected to the stringers of the front part, also having a connection continuity between the front part and the rear part function and enhances the absorption of compressive loads and thus removes the loads from the frame.

The elements in conventional pressure partition wall assemblies, in other words the frames, butt straps, tension fittings and reinforcing frames and struts are usually made of metal. In particular, the frame must of course be made of metal using machining techniques, in view of the fact that the frame must absorb forces by its composition as described above, in view of providing optimum strength and minimum weight at low cost. Therefore, considering the direct solution of manufacturing in composite materials using conventional RTM technology, with which the frame is manufactured in a known assembly structure, which can be considered ideal for this case, still produces serious drawbacks. Firstly, this solution would result in a disproportionate structural member design given the number of layers of oriented fibers that would have to be laid in order to provide the frame with adequate strength. Second, the manufactured frame is prone to delamination problems, especially at the intersection of the center web and upper flange, where forces directed perpendicular to the lamination will concentrate. Third, such a solution would require relatively complex tools due to the relatively complex shape of the frame section.

Contents of the invention

In order to provide a solution to the shortcomings of the prior art, the present invention provides a pressure partition wall assembly that can easily be manufactured entirely in composite materials.

The pressure partition wall assembly of the present invention, like conventional structures, is also designed to connect the front or rear parts of the fuselage corresponding respectively to the pressurized and unpressurized areas in the aircraft. Therefore, the partition wall assembly structure must be able to provide suitable strength for the connection between the front and rear sections of the fuselage and to strengthen the fuselage laterally, in addition to absorbing the pressure loads.

To this end, the claimed pressure partition assembly differs from the known assembly and consists of a simple frame and corner rings, both elements being cylindrically symmetrical (following the contours of the fuselage) as described below and therefore symmetrical by it section definition.

The corner ring has the function of receiving the pressure load from the partition wall. It is characterized in that it is L-shaped, with two rectilinear parts: the front and the rear. The pressure partition is thus connected to the rear of the corner ring, which protrudes upwards and rearwards with respect to the skin at an inclination determined by a line tangent to the pressure partition.

In addition to the above, the simple frame has the function of strengthening the transverse section of the fuselage in a manner independent of the function provided by the corner rings to absorb the pressure loads from the partition walls. For this, the frame has an upper flange, a central web and a lower flange.

A simple frame is attached to the corner rings, and the combined frame and ring is secured to the skin with stiffeners called butt straps between the front of the corner rings and the skin. The front part and the rear part of the skin are fixed to the front part of the corner ring so that the front part of the ring has the function of receiving the connecting forces of the parts of the fuselage.

When placing simple frames on corner rings, it has been found expedient to position the central web of the frame near the corner between the front and rear of the corner rings, in order to give the effect of the simple frame being pressed against the corner rings, which makes The distribution of pressure loads on the corner rings can be improved. In particular, a simple frame can have a lower flange extending only forwards with respect to the central web, which makes it possible to optimize this technical effect.

In order to ensure the continuity of the connection of the front and rear parts of the fuselage and thus the continuity of the forces absorbed by the stringers and skins of the corresponding parts, the assembled structure includes some front tension fittings and rear tension fittings, these tension fittings Attach stringers to butt straps.

With this construction, the need for a simple frame to have to be held in tension as in conventional frames is eliminated, thus eliminating the need for the frame to be made of metal. As a result, forces due to pressure loads are redistributed towards the various parts of the fuselage, avoiding the need to absorb them through conventional frames.

In addition, the assembled structure may include a plurality of stiffeners for avoiding local bending of the simple frame in the assembled structure. These stiffeners are provided along the length of the frame, connecting between the frame and the corner rings.

The simple frame elements, corner rings and butt straps may be formed from a single part or from multiple parts arranged along the length of the fuselage profile. In the latter of these cases, when it is necessary to ensure continuity of stress between the different parts, conventional connection elements such as joint fittings can be installed in place. Specifically, this is required on the frame. Thereby, the panels of each pair in the overlapping sections may be arranged in different frame sections.

In order to connect the different elements making up the assembled structure, both fixing means and connecting means are considered. Fixing means differ from connecting means in that fixing means require connecting elements other than the elements to be connected. Fixing means can be mechanical (threaded, such as screws; or non-threaded, such as blind rivets or non-blind rivets) or chemical (such as adhesives, by bonding or co-bonding; the latter requires parts are made of composite materials). The joining means, likewise, can also be of the mechanical type (tongue-and-groove type) or chemical type (for example by co-curing, which requires that the parts to be joined are made of composite material). The difference between co-curing and co-bonding techniques is as follows: In co-curing, the components to be joined are not previously cured, and the connection is created using the curing of the two components that are combined, rather than between the components to be joined Any adhesive is provided; but in co-bonding, one of the elements to be joined has been cured beforehand and a layer of adhesive is placed between the elements to be joined.

Thus, according to the above, various options for connecting the different elements constituting the assembled structure can be considered according to the different fixing means or connecting means chosen. In particular, when the corner rings, the simple frame and the stiffener are made of composite material, the elements can be connected to one another by co-bonding or also by co-curing.

In addition, the option also includes that the corner rings form an integral part of the pressure partition, so that the partition is manufactured to include the corner rings.

All elements in the assembled structure can easily be manufactured in composite materials due to their proper construction.

Composite materials are defined in the art as materials consisting essentially of small diameter, high strength, high stiffness fibers embedded within a homogeneous material matrix.

Composite materials considered suitable for use in the manufacture of elements of structures in the present invention are organic matrix materials in which the matrix is a thermosetting resin such as epoxy, polyester, phenolic, polyimide or bismaleimide resin ) or thermoplastic resin. On the other hand, suitable materials for fibers are boron or carbon (graphite).

The following manufacturing techniques are considered for obtaining the components in the assembled structure of the present invention:

-RTM: (Resin Transfer Molding). Fibers arranged into a fabric or web are laminated within the mold. The matrix material is then transferred into the mold until it fills the spaces between the fibers, where all the material is compacted. Composites are subjected to temperature and pressure cycles in an oven or autoclave suitable for curing the matrix resin.

- Pre-impregnation: fibers previously impregnated in the matrix material are spread on the surface of the mold, stacked in multiple layers until the required component thickness is reached, and then compacted. The material is spread in layers or impregnated fibers, resulting in different processes known as lay-up or filament winding, respectively. Alternatively, the prepreg process can be combined with thermoforming/stamping techniques, where heat and pressure are used to cause the material to be molded into shape. Composites are subjected to temperature and pressure cycles in an oven or autoclave suitable for curing the matrix resin.

Simple frames or different parts in a frame can utilize Manufactured with RTM technology, resulting in suitable strength and light weight.

Different parts of corner rings or rings can be produced by this technique or by pre-impregnating the surface with composite material in the shape of the ring to be manufactured.

In case the corner ring forms an integral part of the pressure partition wall, the pressure partition wall can be manufactured simultaneously with the corner ring in one piece by prepreg technology, preferably by fiber-laminated prepreg technology.

Butt straps or different parts of butt straps can also be produced by pre-impregnating the composite material on the surface in the shape of the butt strap to be produced.

Finally, all other structural elements (tension fittings and stiffeners) in the assembled structure can be produced by prepreg technology and thermoforming/stamping for realizing additional reinforcement layers.

Description of drawings

The accompanying drawings are provided together with this specification to fully describe the present invention and to help better understand the design features of the present invention:

FIG. 1 is a schematic perspective view of the installation of a pressure partition on an aircraft.

Figure 2 is an A-A' section of the view shown in Figure 1 showing a conventional aircraft pressure partition assembly.

Fig. 3 is an A-A' section of the view shown in Fig. 1, showing an embodiment of an assembled structure of an aircraft pressure partition in the present invention.

Reference signs:

1: Pressure partition wall

2: Pressurized areas in aircraft

3: Unpressurized areas in aircraft

4: The front part of the fuselage

5: Rear part of fuselage

6: Front fuselage skin

7: Rear fuselage skin

8: Front fuselage stringers

9: Rear fuselage stringers

10: Regular frame

11: Front of frame upper flange

12: Rear of flange on frame

13: Conventional frame center web

14: Lower flange of conventional frame

15: Conventional butt lap

16: Conventional front tension accessories

17: Conventional rear tension accessories

18: Simple frame

19: Upper flange of simple frame

20: Central web of simple frame

21: Bottom flange of simple frame

22: corner circle

23: butt lap

24: Front tension accessories

25: Rear Tension Fitting

26: reinforcement plate

Detailed ways

According to the reference numerals used in the figures, Fig. 3 shows an A-A' section of one embodiment of the assembled structure in the present invention.

The structure of the present invention provides a pressure bulkhead assembly 1 for an aircraft and means for joining together the front section 4 and the rear section 5 of the aircraft fuselage. A pressure partition 1 separates a pressurized area 2 from an unpressurized area 3 in an aircraft.

As shown in FIG. 3 , the embodiment comprises a simple frame 18 having an upper flange 19 , a central web 20 and a lower flange 21 .

The corner ring 22 is riveted with a rear portion that slopes upwards and backwards towards the pressure partition wall 1 .

The simple frame 18 rests on the unsloped front of the corner ring 22 , which in turn rests on the butt strap 23 . The assembly of simple frame 18, corner rings and butt straps 23 is riveted to the rear section 7 of the fuselage skin with rivets.

This embodiment includes a reinforcement plate 26 riveted to the central web 20 of the simple frame 18 along the rear edge.

The front portion of the corner ring 22 protrudes forward beyond the contact area of the lower flange 21 of the frame 19 with the corner ring 22 . The following parts are riveted to this extension area: corner rings 22 , stiffeners 26 , butt straps and front part 6 of the skin.

The assembled structure also comprises some front tension fittings 24 and rear tension fittings 25 riveted to the stringers 8,9 and the skins 6,7 in the front 4 and rear 5 sections of the fuselage respectively.

Claims (15)

1. the aircraft pressure partition group assembling structure for being divided by forebody (4) to be connected to trailing portion (5), leading portion (4) and trailing portion (5) correspond respectively to pressurised zone (2) and non-pressurised zone (3); Leading portion (4) and trailing portion (5) include respective stringer (8,9) and covering (6,7);

Comprise:

-angle circle (22), follow fuselage profile its Cylindrical symmetry and extend, symmetrical section is L shape, has front and rear, and rear portion upwards and backward tilts and is connected to partition wall (1);

-simple framework (18), follow fuselage profile its Cylindrical symmetry and extend, symmetrical section has upper flange (19), central web (20) and lower flange (21); The lower flange (21) of simple framework (18) is connected to the front portion at angle circle (22);

-fish plate (23), follows fuselage profile its Cylindrical symmetry and extends, between the front portion being positioned at angle circle (22) and covering (6,7); And

-tension force accessory (24,25), it is connected between fish plate (23) and stringer (8,9).

2. aircraft pressure partition group assembling structure as claimed in claim 1, wherein the covering (6) of the leading portion of fuselage and the covering (7) of trailing portion are fixed to the assembly be made up of simple framework (18), angle circle (22) and fish plate (23) by mechanical device.

3. aircraft pressure partition group assembling structure as claimed in claim 2, wherein the covering of the leading portion of fuselage and the covering of trailing portion are fixed to by mechanical device and are divided by fish plate, corresponding forebody and assembly that the stringer of trailing portion and tension force accessory are formed.

4. aircraft pressure partition group assembling structure as claimed in claim 3, wherein pressure partition group assembling structure comprises the polylith brace panel (26) for avoiding simple framework (18) local bending in addition, and it is connected between the front portion of simple framework (18) He Jiaoquan (22).

5. aircraft pressure partition group assembling structure as claimed in claim 3, wherein angle circle (22) and partition wall (1) form as one.

6. aircraft pressure partition group assembling structure as claimed in claim 3, wherein angle circle (22) is fixed to partition wall (1) by mechanical device.

7. aircraft pressure partition group assembling structure as claimed in claim 3, wherein simple framework is by arrange along fuselage profile and substantially nonseptate multiple frame part is formed to each other; Described each several part is connected to each other by conventional equipment.

8. aircraft pressure partition group assembling structure as claimed in claim 3, wherein simple framework is made up of composite material by RTM technology.

9. aircraft pressure partition group assembling structure as claimed in claim 3, wherein angle circle (22) is made up of composite material by pre-preg technology.

10. aircraft pressure partition group assembling structure as claimed in claim 3, wherein fish plate (23) is made up of composite material by pre-preg technology.

11. aircraft pressure partition group assembling structures as claimed in claim 3, wherein tension force accessory (24,25) is made up of composite material by the pre-preg technology with Heat forming/punching press.

12. aircraft pressure partition group assembling structures as claimed in claim 4, wherein brace panel (26) is made up of composite material by the pre-preg technology with Heat forming/punching press.

13. aircraft pressure partition group assembling structures as claimed in claim 3, its mid-board (1) He Jiaoquan (22) is made up of composite material and utilizes co-curing and/or be total to bonding being connected to each other.

14. aircraft pressure partition group assembling structures as claimed in claim 3, wherein simple framework (18) He Jiaoquan (22) is made up of composite material and utilizes co-curing and/or be total to bonding being connected to each other.

15. aircraft pressure partition group assembling structures as claimed in claim 4, wherein brace panel (26), simple framework (18) He Jiaoquan (22) are made up of composite material and utilize co-curing and/or be total to bonding being connected to each other.